Search

A simple and sensitive fluoroimmunoassay (FIA) based on a heavy-chain antibody (VHH) for rapid detection of fenitrothion was developed. A VHH library was constructed from an immunized alpaca, and one clone recognizing fenitrothion (namely, VHHjd8) was achieved after careful biopanning. It was biotinylated by fusing with the Avi tag and biotin ligase to obtain a fusion protein (VHHjd8-BT), showing both binding capacity to fenitrothion and the streptavidin poly-horseradish peroxidase conjugate (SA-polyHRP). Based on a competitive assay format, the absorbance spectrum of oxidized 3,3',5,5'-tetramethylbenzidine generated by SA-polyHRP overlapped the emission spectrum of carbon dots, which resulted in quenching of signals due to the inner-filter effect. The developed FIA showed an IC50 value of 1.4 ng/mL and a limit of detection of 0.03 ng/mL, which exhibited 15-fold improvement compared with conventional enzyme-linked immunosorbent assay. The recovery test of FIA was validated by standard GC-MS/MS, and the results showed good consistency, indicating that the assay is an ideal tool for rapid screening of fenitrothion in bulk food samples.

The value of conventional magnetic resonance imaging in the differential diagnosis of thyroid nodules is limited; however, the value of multi-parameter diffusion-weighted imaging (DWI) in the quantitative evaluation of thyroid nodules has not been well determined.To determine the utility of multi-parametric DWI including mono-exponential, bi-exponential, stretched exponential, and kurtosis models for the differentiation of thyroid lesions.Seventy-nine patients (62 with benign and 17 with malignant nodules) underwent multi-b value diffusion-weighted imaging of the thyroid. Multiple DWI parameters were obtained for statistical analysis.Good agreement was found for diffusion parameters of thyroid nodules. Malignant lesions displayed lower diffusion parameters including apparent diffusion coefficient (ADC), the true diffusion coefficient (D), the perfusion fraction (f), the distributed diffusion coefficient (DDC), the intravoxel water diffusion heterogeneity (α) and kurtosis model-derived ADC (Dapp), and higher apparent diffusional kurtosis (Kapp) than benign entities (allMultiple DWI parameters including ADC, D, f, DDC, α, Dapp and Kapp could discriminate benign and malignant thyroid nodules. The metrics including D, DDC, Dapp and Kapp provide additional information with similar diagnostic performance of ADC, combination of these metrics may contribute to differentiate benign and malignant thyroid nodules. The ADC calculated with higher b values may not lead to improved diagnostic performance.

To early effectively detect amyloid-beta (Aβ) oligomers, a label-free reusable aptasensor was designed. This aptasensor based on a luminescent nanoscale lanthanum-based metal-organic framework (L-MOF)-armored single-stranded DNA antibody (MOF-armored-anti-DNA antibody) as signal tags and aptamer bound to magnetic beads (Apt-MB) as capture probe. The reusable aptasensor combines signal tag and capture probe with antigen-antibody interaction. When the reusable aptasensor is formed, the strong fluorescence intensity of L-MOF will "turn off" by photo-induced electron transfer from excited states to an unfilled d shell of iron cations on the nanoparticle surface. Upon the presence of Aβ oligomers in serum samples, they can be especially distinguished with the Aβ oligomers aptamer in capture probes and then signal tags are released into the solution for developing the fluorescence aptasensor under excitation/emission 365 nm/430 nm. Meanwhile, the aptamer was recovered from the complex of Aβ oligomers/Apt-MB by heat treatment. When the temperature returns to room temperature, the recovered aptamer in the capture probe can once again bound to the MOF-armored-anti-DNA antibody for reuse. The label-free reusable aptasensor system detection has high sensitivity and selectivity toward Aβ oligomers (LOD = 0.4 pg/mL) and an excellent linear range (0.001-100 ng/mL). This strategy is a fruitful step for the development of reusable aptasensor and may turn on new avenues for the applications of Aβ oligomer detection in clinical diagnosis.Graphical abstract.

Food safety incidents continue to be reported frequently in China. Chinese food safety regulators are challenged with extensive regulatory tasks and increasing pressure from all parties. These regulators need to be recognized as the key factor affecting the regulation of food safety by the Chinese administration. Therefore, this research explores the internal mechanisms of food safety regulator job satisfaction and job engagement, applying a structural equation model. Survey data were collected from 1022 food safety regulators of Guangdong, China for analysis. The results indicate that the degree of job satisfaction and job engagement of food safety regulators in Guangdong was at an intermediate level. Compared with their satisfaction with organizational environment and organizational management, their satisfaction with their work characteristics is the important factor influencing job engagement. To strengthen food safety human resource management, a promotion mechanism and salary system for regulators should be improved in the future. In addition, regulatory enforcement conditions and environments should be optimized in order to enhance regulators' job satisfaction and engagement, thereby, ultimately improving the supervisory level of Chinese food safety control.

Agricultural pollution is extremely serious in China, and agricultural output quantity subsidy makes it even worse. This paper captures the impacts of agricultural subsidy, including quantity subsidy and innovation subsidy, on agricultural pollution. Agriculture output quantity, total pollution or emission, equilibrium price, consumer and producer surplus, government budget, and social welfare are all addressed in this study. The results show that emission-reducing innovation subsidy is better than quantity subsidy because it reduces the pollution from agriculture and profits for the agricultural firm are higher under innovation subsidy than under quantity subsidy. More importantly, output quantity and consumer surplus under innovation subsidy are also larger than those under quantity subsidy if the subsidy rate is not too high. This study finds that the importance of the environment to the consumer, marginal emission, and pollution tax will decrease output quantity, consumer and producer surplus and social welfare; however, agricultural subsidy increases them. Furthermore, this study indicates that innovation subsidy can alleviate the “food quantity safety and quality of environment” dilemma in agriculture.

This paper examines the spillover and competition effects of corporate social responsibility (CSR) with duopoly competition. In employing the assumption that firm CSR increases consumer willingness to pay for the firm's products while consumer willingness to pay decreases for non-CSR firm products, some interesting conclusions are achieved. First, CSR spillover effects increase CSR firm outputs and prices, while CSR spillover has the opposite effect on competitors. Second, CSR spillover decreases total outputs and total social welfare levels. Third, competition effects increase CSR expenditures, and CSR firms' CSR policies are the most robust when non-CSR firms assume a leading position. It is found that total outputs and consumer utilities are highest when CSR firm acts as leader, while the relationships of social welfare among different cases are ambiguous depending on product substitution and spillover effects.

This paper examines the interaction between innovation and financial structure under monopoly. We characterise the effects of debt levels on innovative investment by considering a limited liability effect. On one hand, higher debt levels promote both innovative investment and the outputs. On the other hand, shareholders’ net benefits are reduced by higher debt levels and net profit per debt is correspondingly reduced by higher debt level under positive net profit. More importantly, this study captures the interaction between financial structure and industrial organisation without restriction of the interior point.

A set of fuel supply system, in place of the carburetor, based on ultrasonic atomization is designed. The fuel for the new system which is atomized into micron grade fog grain with ultrasonic system, increases the fuel and air mixing contact area, make the fuel mix more uniform. The experimental results shows that the HC and CO conce-ntration in tail gas of new system has significantly lower,and CO2 is increased, which demonstrates the fuel burning more fully, achieve the effect of energy saving and emission reduction. The cost is quite to carburetor type.

O-mode Doppler reflectometer has been successfully developed as an important diagnostic system on HL-2A. It can be used to measure the turbulence propagation in both plasma edge and confinement zone. The Doppler reflectometer system consists of two fixed frequency homodyne receivers: 15 GHz (corresponding to cutoff density of 0.3×1019 m−3) and 33 GHz (corresponding to cutoff density of 1.35×1019 m−3). The Doppler reflectometry principle and the experimental arrangements on HL-2A are presented. Meanwhile, the experimental Doppler reflectometric spectra under different discharge conditions, with and without ECRH, were obtained. Furthermore, the turbulence propagation velocity change and the profile were also observed in different discharge conditions.

Enhanced confinement has been achieved by the centre fuelling of pellet injection on the HL-2A tokamak. The energy confinement time increases from 50 ms to 140 ms after the pellet injection. Experimental results show that the improvement of the confinement is related to the decrease of the electron heat transport. Several phenomena which may lead to the improved confinement have been observed in the experiments. After the pellet injection the hollow electron temperature profile and the peaked electron density profile can be sustained for about 200 ms, but the improved confinement remains at about 500 ms. Sawtooth features and MHD modes have been observed by soft x-ray array and the Mirnov probes. The weak (or reversed) magnetic shear is thought to be an important cause of the low electron heat transport.

A modulated microwave reflectometry has been successfully developed on HL-2A, which can be used to measure the plasma density profile with time-delay method. This microwave reflectometry has two frequency ranges (26.5 to 40 GHz and 40 to 60 GHz) and it is suitable for measuring the plasma density ranging from 0.8 × 1013 cm−3 to 4.5 × 1013 cm−3. The temporal resolution is 1 ms and the spatial resolution is about 1 cm. This paper will present the basic principle of the microwave reflectometry, parameters calibration of the equipment and the experimental results on HL-2A tokamak.

Who is the best connected researcher? This study uses social network analysis to address this question. Specifically, 1831 papers published in six top knowledge management research journals from 2000 to 2010 are analyzed. Firstly, by analyzing the degree distribution of the network, we find there exist a few researchers who have quite a large cooperation network, and in contrast a large sum of common researchers who have just a few cooperators. Next, we respectively identify 20 authors who have the most connections with others according to degree centrality, who are in the core positions according to closeness centrality and who play the “bridge” roles in the network according to betweenness centrality. Finally, the biggest connected sub-graphs, the 57-Actors Graph is extracted and discussed.

To carry out brand strategies for agricultural products is believed to be an effective way by which China can develop modern agriculture, optimize industrial structure, strengthen product competitiveness, boost industrial productivity, and increase farmers' income. The core competitive strength of agricultural product brands depends on their product quality and technology content. Its value creation is influenced by a number of links such as basic and auxiliary activities, each of which entails a related technology support. The technology support for agricultural product brands includes five elements: production, circulation, marketing, service and auxiliary, all of which interrelate and interact with one another to promote the brand value of agricultural products. China shall engage in the five aspects in order to advance the development of technology support in its agricultural product brands, e.g. idea innovation, personnel development, technological R&D promotion, functional coordination and compatible system establishment.

To evaluate the relationship between epithelial-mesenchymal transition and basal cell-like phenotype breast cancer (BLBC).Three hundred and eighty two cases of breast cancers including basal cell-like, luminal A, luminal B and Her-2 subtypes were collected from 458 cases of invasive breast cancers based on their immunophenotypes. They were then stained immunohistochemically with FOXC-2, vimentin, Syndecan-1 and E-cadherin. The relationship of these markers with the basal cell-like phenotype of breast cancer was studied.Of the 41 BLBC cases, FOXC-2, vimentin and Syndecan-1 were positive in 14 cases (34.1%), 18 cases (43.9%) and 36 cases (87.7%) respectively; E-cadherin expression was reduced in 26 cases (63.4%). The positive rates of FOXC-2 and vimentin were higher in BLBC than in other subtypes of breast cancer (P0.01). The expression of E-cadherin was the lowest among the 4 subtypes of breast cancers (P0.01). Syndecan-1 was positive in the stromal cells adjacent to cancer cells in 17 cases (41.5%) BLBC and the expression was higher than that in other subtypes (P = 0.007). There existed a correlation between FOXC-2 and vimentin expression in BLBC (r = 0.607, P0.01). The rates of positive lymph nodes in FOXC-2 and vimentin positive BLBC cases were 71.4% and 66.7% respectively, and both were higher than those of FOXC-2 and vimentin negative BLBC cases (P = 0.002 and P = 0.001).Epithelial-mesenchymal transition is probably related to the basal cell-like phenotype of breast cancers, and this may be one of the reasons accounting for the different biological behavior of BLBC from other subtypes of breast cancer.

To study the clinicopathologic characteristics of basal-like immunophenotype breast cancer (BLBC).458 cases of female infiltrative breast cancer were studied using immunohistochemical staining with an antibody panel of ER, PR, HER2, Ki-67, CK5/6, CK14 and epidermal growth factor receptor (EGFR) and were classified basing on the immunophenotypes. The clinicopathologic characteristics were compared with other immunophenotypes of breast cancer. 228 of 458 cases of breast cancer were followed up.46 cases of BLBC were screened out among the 458 breast cancers. And histological features of BLBC were analysed including the larger diameter of cancer foci (average 3.3 cm), appearance of squeezing phenomenon of neighboring cell borders (58.7%, 27/46), geography-like distribution of necrosis (52.2%, 24/46), central zone fibrosis (30.4%, 14/46) and lymphoplasmacytic infiltration at the margin and stroma (63.0%, 29/46). There were nuclear pleomorphism with numerous mitoses. The cancer cells were closely arranged, forming irregular solid architectures. There was a high expression (25%) of Ki-67 (43.5%, 20/46). CK5/6, CK14 and EGFR were positive in 58.7% (27/46), 43.5% (20/46) and 65.2% (30/46) respectively. 3-year survival rate of BLBC was 66.9%, lower than the luminal A breast cancer and similar to HER2 over-expression breast cancer.The proportion of BLBC in the group of breast cancers is 10%. BLBC has its distinct histological and cytological features. Currently, it is still necessary to depend on immunophenotyping in making a BLBC diagnosis. BLBC is the one of breast cancer subtypes with the poorest prognosis.

A broadband, O-mode sweeping Doppler reflectometry designed for measuring plasma E × B flow velocity profiles is operated in HL-2A. The main feature of the Doppler reflectometry is its capability to be tuned to any selected frequency in total waveband from 26–40 GHz. This property enables us to probe several plasma layers within a short time interval during a discharge, permitting the characterization of the radial distribution of plasma fluctuations. The system allows us to extract important information about the velocity change layer, namely its spatial localization. In purely Ohmic discharge a change of the E × B flow velocity profiles has been observed in the region for 28 < r < 30 cm if only the line average density exceeds 2.2 × 1019 m−3. The density gradient change is measured in the same region, too.

The fuelling efficiency and injection depth are the fundamental problems of supersonic molecular beam fuelling. In the recent supersonic molecular beam injection (SMBI) experiments, the injection depths of SMBI have been found mainly dependent on the background electron density and temperature, the source gas pressure and temperature. The empirical scaling of SMBI depth was obtained at room temperature. Hydrogen clusters formed in the beam have been observed in the low temperature (source gas at liquid nitrogen temperature) SMBI experiments. It resulted in injection depth greater than 30 cm. Comparing the relationships between injection depths, plasma background parameters and molecular source temperature, the cluster formation phenomena during low temperature MBI are analyzed.